Dynamic label-free imaging of lipid nanodomains

Cell membranes are thought to partition into small (10-100 nm) and transient (<100 ms) lipid platforms or "rafts" to control signaling and trafficking across the membrane. The difficulty in observing such species has made "lipid rafts" a contentious topic. Indirect evidence for their existence has been available for decades, but it has not been possible to reveal their dynamics directly. By exploiting the differences in light scattering from different lipid phases, we achieve dynamic imaging of lipid nanodomains. We observe nanodomain formation, destruction, and coalescence—behaviors previously hypothesized but never observed, yet are critical to their proposed function.